Hydraulic actuator



May 23, 1967 P. s. POFFENBARGER 3,320,859

HYDRAULIC ACTUATOR Filed Oct. 4, 1965 3 Sheets-Sheet l L A A INVENTOR ATTORNEYS y 3, 196'? P. s. PDFFENBARGER 3,320,859

HYDE AULI C ACTUATOR 5 Sheets-Sheet 2 Filed Oct.

7'0 DAST/F EHJVG/V LIA/E y 1967 P. s. POFFENBARGER 3,320,859

HYDRAULI C ACTUATOR Filed Oct. 4, ,1965

3 Sheets-Sheet I5 Afd INVENTOR PEI/P115: Bi /EJ607656 ATTORNEYS United States Patent Ofit'ice 3,320,859 Patented May 23, 1967 3,320,859 HYDRAULIC ACTUATOR Perry 3. Poifenbarger, 1808 Louden Heights Road, Charleston, W. Va. 25314 Filed Oct. 4, 1965, Ser. No. 492,612 2 Claims. (Cl. 91-273) This invention relates to a new and useful hydraulic motor for reciprocating a sucker rod in an oil well.

An object of the invention is to provide an improved expansible chamber motor which includes means for creating a snubbing of the movement of the sucker rod of an oil well pump which is being operated by the motor.

A further object of the invention is to provide an improved hydraulic motor which may be actuated by the pressure of the Well gas which is within the well casing of a well which is to be pumped by a pump actuated by the motor.

A further object is to provide an improved hydraulic motor which is simple in construction, reliable in operation, and which may be economically produced.

The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings, in which an example of the invention is shown, and wherein:

FIGURE 1 is a side elevation view of the hydraulic motor according to the invention;

FIGURE 2 is a sectional view taken substantially along the line 2-2 of FIGURE 1 showing the motor in its position at the beginning of the upward stroke of the pistons;

FIGURE 3 is a fragmentary top plan view of the poppet valve assembly;

FIGURE 4 is a sectional view taken substantially along the line 44 of FIGURE 3; and

FIGURE 5 is a fragmentary sectional view with parts broken away for clarity showing the snap action of the toggle spring in actuating the rocker arm.

Broadly speaking this invention relates to a hydraulic motor for providing reciprocating movement to a member that is preloaded Whether by gravity or by other means for movement in one of the two directions in which the reciprocating movement occurs.

The hydraulic motor essentially comprises two vertically extending, non-coextensive coaxially aligned cylindrical chambers containing pistons which are inter-connected, a capacitor cylinder, two snap acting poppet valves provided with a rocker arm, a valve actuating means connected to one of the pistons and lost motion means connecting the rocker arm and the valve actuating means to control the position of the poppet valves. In the preferred embodiment, the motor is mounted over an oil well and is actuated by gas pressure within the well casing of the well being pumped, but the source of hydraulic pressure can, if desired, he varied without changing the mode of the fundamental operation of the machine.

Referring more in detail to FIGURE 2, it will be seen that the first or balance cylinder is secured at it lower end to a main support generally indicated at 12 by means of a flanged collar 14 and circumferentially spaced bolts 16. The balance cylinder 10 engages a shoulder 18 on the main support member so as to form a bottom seal for the balance cylinder. Two horizontally spaced capacitor cylinders 20 are welded at their upper ends to the lower surface of the main support 12 on opposite sides of the axis of the balance cylinder 10. The capacitor cylinders 20 communicate with the balance cylinder 10 lay means of pipes 22 that extend through the main support and which are provided with valves 26. The lower end of the capacitor cylinders 20 are sealed by bottom walls 28 and are supported in upwardly facing channel members 36. The capacitor cylinders are supported over the well casing by members 21 and 23 more clearly shown in FIGURE 1.

The capacitor cylinders 20 are supplied with a source of gas under pressure through pipe 32. Before entering the capacitor cylinders the supply gas passes through a check valve 34 and a pressure regulator 36.

A second or actuating cylinder 40 is mounted above the balance cylinder 10 by means of a plurality of upstanding support plates 42 connected to a flanged collar 38 welded to the upper end of the balance cylinder. A guide member 44 is connected to the lower end of the actuating cylinder 46) and extends laterally therefrom.

A piston 46 is mounted to reciprocate within the balance cylinder 10 and is connected to another piston 48 slidably disposed within the actuating cylinder 40 by an inter-connecting rod 50 which extends through a brass guide 52 and a felt lubricator 54. A rod 56 is connected to the lower end of piston 46 and extends through a stuffing box generally indicated at 58. Rod 56 is connected to the sucker rod 59 by means of a coupling 57. The effective cross-sectional area of the balance piston 46 is greater than that of the actuating piston 48.

The upper end of the actuating cylinder 40 is screw threaded onto a poppet valve assembly generally indicated at 60, which is more clearly shown in FIGURE 4. The valve assembly 60 comprises a valve body 62 and an inlet poppet valve 64 and an outlet poppet valve 66 which cooperate with valve seats 68 and 70 respectively. These valves are maintained normally closed by the tension of compression springs 72 and 74. A suitable inlet pipe 76 communicates the valve body with the capacitor cylinders 20. The outlet poppet valve 66 communicates with the exterior thereof by means of pipe 78. A control valve 80 shown in FIGURE 2 is mounted in the inlet line 76 for regulating the flow of gas to the actuating cylinder 40. A rocker arm 82 is fixed to a shaft 84 which is rotatably mounted in a pair of supporting brackets 86 extending upwardly from the valve body 62. The rocker arm includes two opposed extensions 88 and 90, each of which is engageable with the upper end of one of the poppet valve stems 92 or 94 upon rotation of the shaft 84. A second rocker arm 96 straddles the first rocker arm 82 and has two depending ears 98 and 100 that are pinned to the shaft 84. Fixed to one end of the shaft is an upwardly extending toggle arm 102 having a laterally extending pin 104, more clearly shown in FIGURE 1. A vertical toggle spring 166 is attached at its upper end to the pin 104 and at its lower end to another pin 108 extending laterally from the valve body 62. The toggle spring serves to maintain a given value in an open position until the valve actuating means causes the rocker arm 82 to move to an alternate position.

The valve actuating mechanism generally indicated at 111), as best seen in FIGURE 2, comprises a vertical tube 112 fastened to the lower piston 46 and which extends through guide member 44 and telescopes over rod 114 fastened to the laterally extending member 116 connected to the valve body 62. An actuating rod 118 is connected to the straddle rocker arm 96 by means of a pivot link 120. A collar 121 is attached to tube 112 and can be slid and locked along the tube. A finger member 122 is slidably mounted on tube 112 and actuating rod 118 above collar 121. A spiral spring 124 surrounds the rod 118 and is connected at its lower end to the finger 122 and at its upper end to collar 126 fixed on rod 118. Another finger member 128 is slidably mounted on tube 112 and actuating rod 118 below collar 121. A spiral spring 130 surrounds the rod 118 and is connected at its upper end to finger member 128 and at its lower end to collar 132 fixed on rod 118. Both collars 126 and 132 are adjustably mounted on rod 118 as by set screws so as to he slid and locked in place.

In operation, valves 26 are opened to communicate the apacitor cylinders with one another and the balance vylinder It) and a constant gas pressure is introduced into he capacitor cylinders through pipe 32. Since the parts ire in the position shown in FIGURE 2, the gas will flow )nly into the lower end of the balance cylinder 10. The gas pressure regulator 36 is adjusted so that the pressure )f the gas within the capacitor cylinders 20 is sufiicient to )alance the weight of the sucker rod 59 and pump plunger :not shown) as well as the weight of the oil in the tubing )f the well being lifted by said plunger. For example, if he oil and sucker rod weigh 6000 pounds then the gas )ressure required to support them would be 60 pounds aer square inch with a balance piston area of 100 square nches. Since the pressure acting on the actuating piston 48 is less than the pressure acting against the underside of Jalan-ce piston 46, the balance piston 46 moves upwardly .n its cylinder causing the sucker rod 59 and pump plunger [not shown) to be moved upwardly also. Toward the and of the upstroke of the balance piston 46, the valve actuating means closes the discharge poppet valve 66 and for a period of time both valves are closed so as to provide a snubbing of the movement of the piston 48. As the balance piston 46 continues rising the valve actuating means changes the position of the rocker arm 96 whereby the inlet poppet valve 64 is opened. The upper surface of the actuating piston 48 is then exposed to the pressure of the gas in the capacitor cylinder which causes the piston to move downwardly. As the piston 46 in the balance cylinder 10 is moved downward the pressure in the capacitor cylinders 26 increase since check valve 34 does not permit the gas to escape. This pressure increase provides a snubbing of the movement of piston 46. In the event that the snubbing action is not great enough to retard the piston 46 with its accumulated weight, then it may be necessary to use a hydraulic snu'bber or reduce the ratio of volume of the balance cylinder 10 to the capacitor cylinders 20, when the balance piston 46 is near the bottom of its stroke the intake poppet valve 64 is closed and the discharge poppet valve 66 is opened 'by the valve actuating means and the cycle is repeated. The operating speed of the motor can be controlled by regulating the speed of flow of gas from the capacitor to the actuating cylinder by means of valve 80 in the line to the actuating cylinder or by restricting the fiow gas from the discharge line 134.

Although the illustrated embodiment shows a pair of capacitor cylinders communicating with one another through the expansible chamber created by the balance cylinder and balance piston, it is to be understood only one properly dimensioned capacitor cylinder could be used.

The foregoing description of the invention is explanatory thereof and various changes in the size, shape and materials, as well as in the details of the illustrated construction, may be made, within the scope of the appended claims, without departing from the spirit of the invention.

What is claimed is:

1. A hydraulic motor for reciprocating a sucker rod in an oil well comprising a pair of non-coextensive coaxially aligned cylinders, a first reciprocating piston located within the first of said cylinders to define a first expansible chamber, a second reciprocating piston located within the second of said cylinders to define a second expansible chamber, a first rod means rigidly connecting said first piston and said second piston, a second rod means connected to said first piston and extending without the first expansible chamber for connection with the sucker rod, said respective cylinders and pistons being so dimensioned that the effective area of said first piston is greater than the efiective area of said second piston, a capacitor chamber, means for supplying a source of fluid under pressure to said capacitor chamber, communication means between said capacitor chamber and said first expansible chamber, communication means between said capacitor chamber and said second expansible chamber, a first valve interposed in said last mentioned communication means, a second valve connecting said second expansible chamber with the exterior thereof, valve actuating means connected to said pistons to reciprocate therewith, valve closure means urging each of said valves to a closed position, a valve opcrating rocker arm mounted juxtaposed said valves to alternately open and shut said valves by alternately impinging thereupon, lost motion means connecting said rocker arm to said valve actuating means whereby the first valve is open and the second valve is closed upon the approach of the pistons to a one extreme position, and whereby the first valve is closed and the second valve is open upon the approach of the pistons to the other extreme position, said rocker arm being so positioned that during one period of its movement it does not impinge upon either valve whereby both valves remain closed to provide snubbing of the movement of the second piston when the same is moving toward said second valve.

2.'A hydraulic motor for vertically reciprocating a sucker rod in an oil well to lift oil from the well comprising two non-coextensive coaxially vertically aligned cylinders including a larger diameter balance cylinder and a smaller diameter actuating cylinder; a first balance piston arranged to slidingly reciprocate within the balance cylinder, and defining with said balance cylinder an expansible-contractile chamber therebelow; a second actuating piston arranged to slidingly reciprocate within the actuating cylinder, and defining with said actuating cylinder an expansible contractile chamber thereabove; means rigidly connecting the balance and actuating pistons to one another for coreciprocation between an upper end point wherein the balance cylinder chamber is expanded and the actuating cylinder chamber is contracted and a lower end point wherein the actuating cylinder chamber is expanded and the balance cylinder chamber is contracted; means rigidly connecting the balance piston to a sucker rod in the well; means defining a capacitor chamber communicated to said balance cylinder chamber by means con structed and arranged to allow reversible fluid flow between said capacitor chamber and said balance cylinder chamber; a source of constant fluid pressure communicated to said capacitor chamber means through non-rcturn valve means; conduit means connected at one end to said actuating cylinder chamber and communicating at the opposite end thereof with said capacitor chamber means and said balance cylinder chamber, said conduit means being constructed and arranged to communicate fluid pressure to the actuating cylinder chamber; a well products collection line connected to said actuating cylinder chamber; valve means interposed in said conduit means and said well products collection line and being operable to alternately establish and break communication between the actuating cylinder chamber and said conduit means and collection line; valve actuator means for said interposed valve means, said valve actuator means being responsive to the reciprocating travel of said pistons, said rigid connecting means and sucker rod including being responsive to the approach of said pistons, said rigid connecting means and sucker rod to said upper and lower end points, said valve actuator means being constructed and arranged to serially, cyclically:

(a) establish communication between said actuating cylinder chamber and said collection line when the pistons, rigid connecting means and sucker rod are near said lower end point to allow said balance piston to be lifted by fluid pressure from said source of constant fluid pressure via said capacitor, until said pistons rigid connecting means and sucker rod are near said upper end point;

(b) break communication between said actuating cylinder chamber and said collection line as said pistons, connecting means and sucker rod near said upper end point to thereby cushion the approach of said pistons, rigid connecting means and sucker rod to said upper end point;

5 6 (c) establish communication between said conduit quanta of fluid under pressure and expent quanta means and said actuating cylinder chamber upon atare collected by said collection line. tainrnent by said pistons, rigid connecting means and sucker rod of said upper end point to thereby References Cited by the Examiner spoil lifting of said balance piston thus allowing said 5 pistons, rigid connecting means and sucker rod to fall UNITED STATES PATENTS toward said lower end point; and 950,893 3/1910 Conboy et a1. 91-273 ((1) break toward said lower end point communication 1, 67,613 7/ 1913 Lane 9l347 between said conduit means and said actuating cyl- 2,406,747 9/1946 Davis 91-321 inder chamber upon approach of said pistons, rigid 10 2,712,302 7/1955 Zoller 91-321 connecting means and sucker rod to said lower end 2,916,205 12/1957 Litz 92-152 point thereby cushioning the approach of said pistons, rigid connecting means and sucker rod to said MARTIN p SCHWADRON primary Examiner, lower end point; whereby said pistons, rigid connecting means and sucker rod are repeatedly lifted by 15 PAUL MASLOUSKY, Examiner- 

1. A HYDRAULIC MOTOR FOR RECIPROCATING A SUCKER ROD IN AN OIL WELL COMPRISING A PAIR OF NON-COEXTENSIVE COAXIALLY ALIGNED CYLINDERS, A FIRST RECIPROCATING PISTON LOCATED WITHIN THE FIRST OF SAID CYLINDERS TO DEFINE A FIRST EXPANSIBLE CHAMBER, A SECOND RECIPROCATING PISTON LOCATED WITHIN THE SECOND OF SAID CYLINDERS TO DEFINE A SECOND EXPANSIBLE CHAMBER, A FIRST ROD MEANS RIGIDLY CONNECTING SAID FIRST PISTON AND SAID SECOND PISTON, A SECOND ROD MEANS CONNECTED TO SAID FIRST PISTON AND EXTENDING WITHOUT THE FIRST EXPANSIBLE CHAMBER FOR CONNECTION WITH THE SUCKER ROD, SAID RESPECTIVE CYLINDERS AND PISTONS BEING SO DIMENSIONED THAT THE EFFECTIVE AREA OF SAID FIRST PISTON IS GREATER THAN THE EFFECTIVE AREA OF SAID SECOND PISTON, A CAPACITOR CHAMBER, MEANS FOR SUPPLYING A SOURCE OF FLUID UNDER PRESSURE TO SAID CAPACITOR CHAMBER, COMMUNICATION MEANS BETWEEN SAID CAPACITOR CHAMBER AND SAID FIRST EXPANSIBLE CHAMBER, COMMUNICATION MEANS BETWEEN SAID CAPACITOR CHAMBER AND SAID SECOND EXPANSIBLE CHAMBER, A FIRST VALVE INTERPOSED IN SAID LAST MENTIONED COMMUNICATION MEANS, A SECOND VALVE CONNECTING SAID SECOND EXPANSIBLE CHAMBER WITH THE EXTERIOR THEREOF, VALVE ACTUATING MEANS CONNECTED TO SAID 